﻿using System;

class Program
{
    static void Main()
    {
        int n=int.Parse(Console.ReadLine());
        int k=int.Parse(Console.ReadLine());
        float fn=1;
        float fk=1;
        do
        {
            fn *= n;
            n--;
        }
        while (n > 0);
        do
        {
            fk *= k;
            k--;
        }
        while (k > 0);
        Console.WriteLine(fn/fk);
    }
}